1. Field of the Invention
This invention relates of a magnetic recording and reproducing apparatus and to a cleaning cassette for cleaning a head or heads and tape guides of the magnetic recording and reproducing apparatus
2. Description of the Related Art
In a rotary head type VTR, troubles may arise in the recording or reproducing of an image or sound due to clogging of a head by magnetic powders or the like or by the depositing of nicotine from cigarettes or other tobacco products on tape guide pins or the like. Therefore, cleaning cassettes are commercially available for cleaning the heads or guide pins of VTRs or other magnetic recording and reproducing apparatus Such cleaning cassettes may include a dry type cleaning tape or a wet type cleaning tape. In the case of a cleaning cassette with a dry type cleaning tape, the head is rubbed by a material, such as, so-called emery cloth, for removing magnetic particles or dust therefrom. In the case of the wet type cleaning tape, the head is polished by a material, such as, toweling, soaked with a cleaning liquid for once again removing particles or dust adhering to the head.
The methods of using the dry type cleaning tape and the wet type cleaning tape are similar. In each case, the cleaning cassette has a housing with a shape similar to that of a normal tape cassette. The cleaning cassette is loaded into a VTR in place of the normal video tape cassette and the cleaning tape is fed or advanced by the VTR in its reproducing or recording mode for a predetermined time of about 10 to 20 seconds. When the cleaning cassette is loaded into the VTR and its cleaning tape is fed as mentioned above, the head and/or guide pin or pins of the VTR are rubbed by the driven cleaning tape so that dust on the heads and/or guide pins are removed or eliminated.
As already mentioned, the dry type cleaning tape is of a material like emery cloth, and the wet type cleaning tape is of a coarse material like toweling soaked with a cleaning liquid. In either case, the cleaning tape is relatively coarse. Therefore, when the cleaning cassette is used, it is necessary to pay careful attention to the cleaning time, that is, the length of time during which the cleaning tape is rubbed against the head or heads. If the cleaning cassette is used for a time longer than a specified cleaning time, the head is abraded and, in extreme cases, this may result in serious damage to the head or heads. Moreover, the material or coarseness of the cleaning tape differs with the company which manufactures the cleaning cassette. Therefore, the cleaning times of several cleaning cassettes may differ from one company to the next at which such cleaning cassettes respectively originate.
In the known cleaning cassettes, the cleaning time is printed or otherwise noted on the cassette casing or on a label affixed thereto. It is intended that the user will make note of the recommended cleaning time and pay attention thereto when using the cleaning cassette in a VTR or other recording and reproducing apparatus. When the recommended cleaning time elapses, the cleaning cassette is replaced by a normal tape cassette, and the VTR is then operated in its playback or reproducing mode to permit monitoring of a reproduced image. If defects are observed in the reproduced image, the normal tape cassette is again replaced by the cleaning cassette and the cleaning operation is repeated. The noted cleaning and reproducing operations are alternately repeated until the quality of the reproduced image indicates that head and guide pin cleaning have been adequately achieved.
Since the head is abraded each time the cleaning cassette is used, the number of repeated uses of the cleaning cassette for achieving adequate cleaning of the head is limited. Further, when the cleaning cassette is used repeatedly, dusts are deposited on, and adhere to the cleaning tape, or the originally relatively coarse surface of the cleaning tape is worn or rendered smooth so that the cleaning effect of the cleaning tape is reduced or extinguished. Therefore, there is also a limitation in respect to the total number of times that the cleaning cassette can be used. Such limitations in the number of times that the cleaning cassette should be used in any one cleaning operation and in the total number of times the cleaning cassette may be used without losing its effectiveness also differ from one manufacturer of cleaning cassettes to the next.
The cleaning tape materials also differ in dependence upon the type of recording or reproducing apparatus for which the cleaning cassette is intended. For example, a magnetic material is more coarsely coated onto a tape of the cleaning cassette for an industrial-use VTR as compared with the tape of a cleaning cassette intended for a business-use VTR. Therefore, the industrial-use cleaning cassette can be repetitively used by rewinding the tape in the casing of the cleaning cassette so long as the number of uses lies within the permissible total number thereof. In the case of a cleaning cassette for a business-use VTR, however, the effectiveness of the cleaning cassette is ordinarily substantially diminished if not substantially exhausted after the full length of the cleaning tape has been used a single time. Furthermore, the tape material of a cleaning cassette for a computer or data streamer differs from the tape material of a cleaning cassette for a VTR.
As mentioned above, prior to using the conventional cleaning cassette, the user must carefully read the instructing notes printed or otherwise applied to the cassette casing and pay attention to the permissible cleaning time for each use, the number of times the cleaning cassette may be used for each cleaning operation, and the total number of times the cleaning cassette may be used. However, there is the possibility that the user may ignore such instructions or may not correctly understand the same, in which case damage to the head or heads of the VTR or other recording and reproducing apparatus may result.
For example, if the user replaces a previously used cleaning cassette with a cleaning cassette of a different kind or originating with a different company, the user may not be aware that the specified cleaning time for the new cleaning cassette is different. In such case, if the new cleaning cassette is used for a period of time longer than the recommended cleaning time therefor, the head or heads may be damaged.
Further, if a user erroneously employs a conventional cleaning cassette as a normal video cassette, serious damage to the head or heads frequently occurs. Since the conventional cleaning cassette has exactly the same shape as the normal video cassette, the user is liable to mistake the cleaning cassette for a normal video cassette and to load it into the VTR and then select the reproducing or play mode. In this case, so long as the user does not become aware of the mistake, the cleaning tape is continuously rubbed against the head or heads. Although no image or sound is produced when the cleaning tape is scanned by the head or heads, the user may not properly infer therefrom that a cleaning tape has been loaded. Rather, the user may firmly believe that a normal video cassette has been loaded and may conclude that the reason why no image or sound is generated is because the VTR has failed or a wire is disconnected. Thus, the user may repeatedly try to reproduce or play back the cleaning tape with the VTR in its reproducing or play back mode with the result that the head or heads suffer undesirable abrading by the cleaning tape.
When a user erroneously assumes a cleaning cassette is a normal video cassette and loads it into a VTR which is then preset to automatically initiate a recording operation at a future time, a tragic result may occur. In such case, the recording operation will likely be initiated at a time when the VTR is unattended so that no one will be aware that a cleaning operation, and not a normal recording operation is being effected. Since the tape length of the normal cleaning cassette corresponds to a running time of about 15 minutes, even in the long-time recording mode, the cleaning tape is fed for a long time, for example, at least as much as 30 minutes or more, under the described circumstances so that serious damage to the head or heads cannot be avoided.